Grundfos system problem

I have possibly two problems with my Grundfos system. First the CU 301 has gone bad, yesterday I lost all water and the CU 301 had no lights lit on the front panel at all, inside one green led is lit and 2 flashing. I called the guy who put the system in and he said a low voltage coil in the CU 301 has gone bad and I need to replace the unit.

We live in the sticks not near any other water sources to fill buckets so I asked him about bypassing the unit so I could get some water to fill buckets and so on. He told me how to wire the pump directly but cautioned I would have high pressure that could damage things in the house so make sure I had the outside faucets running all the time to keep the pressure down, as long as I did this I could use the system for whatever I needed.

Here's where I think there may be a second problem. I opened 1 outside faucet and turned the breaker to the pump on, it started slow and in about 45seconds it was at 73 lbs, I turned on my outside sprinkler system and it dropped to about 60 lbs, the longer it ran the more the pressure decreased. After about 15 mins it dropped to 45 lbs, I closed the outside faucet a bit and it increased to about 50 lbs, by the time the sprinlker system had started it's 3rd zone, about 30 mins, I had the outside faucet totally closed and the system would only muster 35 lbs. Does this sound like I have a problem with the pump also? I'd appreciate any help you could give me.

I don't know a CU 301 but it sounds like a controller for a variable speed constant pressure pump system. I can't help you get water or figure out what is wrong with the pump operation but, in case you have a bad pump...

Many of those systems fail as yours has. They are expensive to repair and cost more than a regular pump, small pressure tank and a constant pressure valve called a CSV (Cycle Stop Valve). With a regular pump, CSV and small pressure tank there are no electronics to go bad and a regular pump doesn't run at the extremely high rpm of a variable speed pump that has its rpm constantly being increased or decreased.

I would think the well should have enough water to run the small sprinkler system I have, there's 8 sprinkler heads per zone and each zone is set for 15 mins, 3 zones. The well was was put in 3 1/2 years ago and the well report says 14 gpm? The well is 240'.

You probably just overpumped the well when you had the hose and the sprinkler system on at the same time. Try running the sprinkler zones like normal and see what happens. I think your worst case might be that you need to program in some time between zones for the well to recover.

You should be able to run all three zones at the same time. This would only be 9.6 GPM. One zone at a time should not be a problem at 3.2 GPM. You will need something like a Cycle Stop Valve to run less GPM than the pump can produce.